DTC U0128 (Gauge Control Module (Without CAN Gateway)) (2017 2018 2019 2020)

DTC U0128  : Gauge Control Module Lost Communication With Electric Parking Brake Control Unit

DTC Description	DTC
U0128 Gauge Control Module Lost Communication With Electric Parking Brake Control Unit

DTC (Gauge Control Module)

NOTE: 

• Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information - Refer to:

  How to Troubleshoot the Fuel and Emissions Systems (2014 2015 2016 2017 2018 2019 2020) or

  How to Troubleshoot the Fuel and Emissions Systems (With Auto Idle Stop System) (2016 2017 2018 2019 2020)

• If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2017 2018 2019 2020)

1. Problem verification

   - 1. Clear the DTCs with the HDS.

   - 2. Turn the vehicle to the OFF (LOCK) mode and then the ON mode.

   - 3. Wait for at least 6 seconds.

   - 4. Check for DTCs with the HDS.

   DTC Description	DTC
   U0128 Gauge Control Module Lost Communication With Electric Parking Brake Control Unit

   Is DTC U0128 indicated?

   YES 

   Go to step 2.

   NO 

   Intermittent failure, the system is OK at this time. Check for loose or poor connections.

2. Fuse check

   - 1. Check the following fuse.

   Fuse	No. F13 (7.5 A)
   Location	Rear fuse/relay box

   Is the fuse OK?

   YES 

   Go to step 3.

   NO 

   Replace the fuse. If the fuse blows again, repair a short to ground in the No. F13 (7.5 A) fuse circuit.

3. Open wire check (IG1 ECU RR line)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Disconnect the following connector.

   Electric parking brake control unit 30P connector

   - 3. Turn the vehicle to the ON mode.

   - 4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode Electric parking brake control unit 30P connector: disconnected
   Test point 1	Electric parking brake control unit 30P connector No. 24
   Test point 2	Body ground

   Is there battery voltage?

   YES 

   The IG1 ECU RR wire is OK. Go to step 4.

   NO 

   Repair an open or high resistance in the wire.

4. Open wire check (PGND lines)

   - 1. Turn the vehicle to the OFF (LOCK) mode.

   - 2. Check for continuity between test points 1 and 2.

   Test condition	Vehicle OFF (LOCK) mode Electric parking brake control unit 30P connector: disconnected
   Test point 1	Electric parking brake control unit 30P connector No. 5
   Test point 2	Body ground

   Test point 1	Electric parking brake control unit 30P connector No. 7
   Test point 2	Body ground

   Are there continuity?

   YES 

   The PGND wires are OK. Go to step 5.

   NO 

   Repair an open or high resistance in the ground wire or poor ground (G603/G606).

5. Open wire check (F-CAN A lines)

   - 1. Disconnect the following connector.

   Gauge control module connector A (32P)

   - 2. Check for continuity between test points 1 and 2 respectively.

   Test condition	Vehicle OFF mode EPS control unit connector A (11P): disconnected Gauge control module connector A (32P): disconnected
   Test point 1	Gauge control module connector A (32P) No. 27 - Refer to: Gauge Control Module Input Test (2017 2018 2019 2020)
   Test point 2	Electric parking brake control unit 30P connector No. 30

   Test point 1	Gauge control module connector A (32P) No. 28 - Refer to: Gauge Control Module Input Test (2017 2018 2019 2020)
   Test point 2	Electric parking brake control unit 30P connector No. 29

   Is there continuity?

   YES 

   The F-CAN A wires are OK. Replace the electric parking brake control unit .

   NO 

   An open or poor connection in the F-CAN A wires.